1. Technical Field
This invention relates to radially acting dynamic shaft seals, which include a PTFE seal element.
2. Related Art
It is common in shaft seal applications to employ a PTFE seal element. The PTFE element can be secured to a rigid annular casing of the seal assembly either by clamping the element between joined case members, or by bonding the PTFE element to the casing by an intermediate elastomer material such as rubber. It is also known to provide the rubber material with a flex joint to enable the PTFE element to flex and remain in sealing contact with the shaft during conditions of shaft run out where the shaft becomes displaced radially from its true center of rotation.
It is also common to form one or more sealing lips from the elastomer material that may also run in sealing contact with the shaft to enhance sealing performance.
It is an object of the present invention to improve upon such seals, and in particular the flexibility and sensitivity of the PTFE and rubber sealing lips.